Question 1051590
 A juice seller sells juice in small, medium and large glasses. 

The cost of a small glass is Rs 7, the cost of a medium glass is Rs 10 and the 
cost of a large glass is Rs 12. 

The number of small glasses of juice sold was x. 

The number of medium glasses of juice sold was twice the number of small 
glasses of juice sold:: 2x 

The number of large glasses of juice sold was 20 more than the medium glasses 
of juice sold:: 2x+20 

Given that Rs 2790 was received from the sale of the juice, find the total number of glasses of juice sold.
-------------------------------
Value Equation::
value + value + value = value
7x + 10(2x) + 12(2x+20) = 2790
-----
(7 + 20 + 24)x  = 2790-12*20
51x = 2550
---
x = 50 (# of small)
2x = 100 (# of medium)
2x+20 = 120 (# of large)
-----------
Cheers,
Stan H.
----------